Conventionally, a cylindrical vibration-damping device equipped with outer bracket (hereinafter referred to as a “cylindrical vibration-damping device”) is known as one type of vibration damping connectors or vibration damping support that is placed between the components that make up the vibration transmission system, it provides a vibration damping connection between those components, and it is applicable to automotive engine mounts, etc. The cylindrical vibration-damping device as stated in U.S. Pat. No. 6,105,944 (Patent Document 1), for example, features a structure wherein an outer bracket is attached to a vibration damping device main unit that is provided with a vibration damping rubber on the outer circumference of an inner shaft member, and the outer bracket is equipped with a mounting hole which is fixed externally onto the outer peripheral surface of the vibration damping rubber.
Incidentally, because the vibration damping rubber in Patent Document 1 is installed in the mounting hole of the outer bracket in a non-adhesive way, an inner projection that protrudes toward the inner circumference is formed at each axial end of the peripheral wall of the outer bracket that forms the mounting hole for the purpose of maintaining the position of the vibration damping rubber and preventing it from falling out of the mounting hole.
However, when you attempt to integrally form the inner projections at both axial ends of the peripheral wall of the outer bracket, a problem arises wherein removal of the mold in the axial direction becomes impossible due to the inner mold (core) that is used to form the inner peripheral surface of the peripheral wall getting caught on the inner projections during formation of the die for the peripheral wall. Thus, in order to mold an outer bracket that is equipped with an inner projection, it was necessary to use a sand mold for the inner mold and destroy and remove that inner mold after molding the outer bracket, so efficient manufacturing was difficult due to the increased number of manufacturing processes and the increased cost required.
Because the vibration damping rubber in Patent Document 1 was also positioned in the axial direction through contact with the inner projection that is formed at each axial end of the peripheral wall, it became necessary to increase the size of the outer peripheral end of the vibration damping rubber in the axial direction, so there existed the possibility that flexibility in tuning the spring characteristics would be decreased.